The present disclosure relates to a memory element storing information based on a change of electrical characteristics observed in a memory layer including an ion source layer and a resistance change layer, and to a memory device.
A semiconductor nonvolatile memory popularly used for data storage has been an NOR or an NAND flash memory. Such a semiconductor nonvolatile memory, however, has been pointed out that there are limitations on microfabrication considering the need for a high level of voltage for writing and erasing, and the limited number of electrons for injection to a floating gate.
For overcoming such limitations on microfabrication, a next-generation nonvolatile memory currently proposed is a resistance change memory such as ReRAM (Resistance Random Access Memory) or PRAM (Phase-Change Random Access Memory) (for example, see Japanese Unexamined Patent Application Publication No. 2006-196537, and Waser et. al, Advanced Materials, 21, p2932 (2009). These memories are each in the simple configuration including a resistance change layer between two electrodes. In a memory of Japanese Unexamined Patent Application Publication No. 2009-43757, as an alternative to the resistance change layer, an ion source layer and an oxide film (thin film for storage) are provided between first and second electrodes. With the resistance change memories as such, it is understood that a resistance value changes by a conductive path formed as a result of the movement of atoms or ions by heat or an electric field.